Electronically tunable ceramic materials including tunable dielectric and metal silicate phases

Abstract

The present invention relates to electronically tunable dielectric materials which have favorable properties for many applications, including the area of radio frequency (RF) engineering and design. The electronically tunable materials include an electronically tunable dielectric phase such as barium strontium titanate in combination with a metal silicate phase such as Mg2SiO4. The electronically tunable materials may be provided in bulk, thin film and thick film forms for use in devices such as phased array antennas, tunable filters and the like.

What is claimed is:  
     
       1. An electronically tunable dielectric material comprising; 
       at least one electronically tunable dielectric phase comprising barium strontium titanate; and  
       at least one metal silicate phase comprising a silicate of at least one metal selected from Be, Mg, Ca, Sr, Ba, Ra, Li, Na, K, Rb, Cs, Al, Zr, Zn, Fr, B, Fe, Mn, Cu, Ce, Cr, La, Y, Ti, Ta, Nb, Mo, W, Ni, Pd, Pb and Bi, wherein the metal silicate comprise from about 5 to about 65 weight percent of material.  
     
     
       2. The electronically tunable dielectric material of  claim 1 , wherein the metal silicate phase comprises a silicate of at least one metal selected from Mg, Ca, Sr and Ba. 
     
     
       3. The electronically tunable dielectric material of  claim 1 , wherein the metal silicate phase comprises Mg 2 SiO 4 , CaSiO 3 , BaSiO 3  and/or SrSiO 3 . 
     
     
       4. The electronically tunable dielectric material of  claim 1 , wherein the barium strontium titanate is of the formula Ba x Sr 1−x TiO 3 , where x is from about 0.15 to about 0.6. 
     
     
       5. The electronically tunable dielectric material of  claim 1 , wherein the metal silicate comprises from about 10 to about 50 weight percent of the material. 
     
     
       6. The electronically tunable dielectric material of  claim 1 , further comprising up to about 10 weight percent of at least one additional oxide material selected from oxides of Ba, Mg, Zr, Ca, Fe, Sr, Nb, Ta, Cr, Sn, Mn, W, Al, Ti, Na, K, Nd, Pr, Y and La. 
     
     
       7. The electronically tunable dielectric material of  claim 1 , wherein the material has a tunability of at least 10 percent at 8 V/micron. 
     
     
       8. The electronically tunable dielectric material of  claim 1 , wherein the material has a tunability of at least 25 percent at 8 V/micron. 
     
     
       9. A method of making an electronically tunable dielectric material comprising: 
       mixing particles of at least one electronically tunable dielectric material and particles of at least one metal silicate material, wherein the electronically tunable dielectric material comprises barium strontium titanate, the metal silicate material comprises a silicate of at least one metal selected from Be, Mg, Ca, Sr, Ba, Ra, Li, Na, K, Rb, Cs, Al, Zr, Zn, Fr, B, Fe, Mn, Cu, Ce, Cr, La, Y, Ti, Ta, Nb, Mo, W, Ni, Pd, Pb and Bi, and the metal silicate comprises from about 5 to about 65 weight percent of the material; and  
       sintering the material.  
     
     
       10. The method of  claim 9 , wherein the electronically tunable dielectric particles and the metal silicate particles have average particle sizes of from about 0.1 to about 5 micron. 
     
     
       11. The method of  claim 9 , wherein the electronically tunable dielectric particles and the metal silicate particles have average particle sizes of from about 1.5 to about 2.5 micron. 
     
     
       12. The method of  claim 9 , wherein the metal silicate material comprises a silicate of at least one metal selected from Mg, Ca, Sr and Ba. 
     
     
       13. The method of  claim 9 , wherein the metal silicate material comprises Mg 2 SiO 4 , CaSiO 3 , BaSiO 3  and/or SrSiO 3 . 
     
     
       14. The method of  claim 9 , wherein the barium strontium titanate is of the formula Ba x Sr 1−x TiO 3 , where x is from about 0.15 to about 0.6. 
     
     
       15. The method of  claim 9 , wherein the metal silicate comprises from about 10 to about 50 weight percent of the sintered mixture. 
     
     
       16. The method of  claim 9 , further comprising adding up to about 10 weight percent of at least one additional oxide material selected from oxides of Ba, Mg, Zr, Ca, Fe, Sr, Nb, Ta, Cr, Sn, Mn, W, Al, Ti, Na, K, Nd, Pr, Y and La to the electronically tunable dielectric and metal silicate particles. 
     
     
       17. The method of  claim 9 , wherein the sintered mixture has a tunability of at least about 10 percent at 8 V/micron. 
     
     
       18. The method of  claim 9 , wherein the sintered mixture has a tunability of at least about 25 percent at 8 V/micron.